For example, integrated coal gasification combined cycles are power generation facilities which gasify coal, and are combined with combined cycle power generation thereby aiming at increasing efficiency and environmental performance higher compared to related-art coal-fired power generation. The integrated coal gasification combined cycles have a great advantage that coal having a large amount of resources is also available. It is known that the advantage becomes greater by increasing applied kinds of coal.
Generally, the related-art integrated coal gasification combined cycles have a coal supply apparatus, a drying apparatus, a coal gasification apparatus, a gas purifying apparatus, a gas turbine facility, a steam turbine facility, a heat recovery steam generator, a gas cleaning apparatus, and the like. Accordingly, coal is pulverized after dried, and is supplied as pulverized coal to the coal gasification apparatus, air is taken in, the coal is combusted and gasified in this coal gasification apparatus, and produced gas (inflammable gas) is produced. Then, as this produced gas is supplied to the gas turbine facility after being purified, the produced gas is combusted to produce high-temperature high-pressure combustion gas to drive a turbine. The heat energy of the exhaust gas after driving the turbine is recovered by the heat recovery steam generator to produce steam, and the steam is supplied to the steam turbine facility to drive the turbine. Accordingly, power generation is performed. Meanwhile, the exhaust gas of which the heat energy is recovered is emitted to the atmospheric air via a chimney after harmful substances are removed by the gas cleaning apparatus.
In the coal gasification apparatus in the integrated coal gasification combined cycles, the gasification furnace is positioned inside the pressure vessel, a heat exchanger (gas cooler) is configured so as to be positioned on an upper side of the gasification furnace, and a space section between the pressure vessel and the gasification furnace is filled with seal gas. As such a coal gasification apparatus, there is, for example, one described in the following PTL 1. In the pressurization type gasification furnace described in this PTL 1, water-cooled walls are provided at a distance inside a pressure-resistance vessel, a space section between both of the walls and the interior of a furnace body are made to communicate with each other by piping, and a pressurizing and purifying gas is supplied to the space section according to the differential pressure between both the space section and the furnace body, thereby equalizing the pressure of the space section and the interior of the furnace body.
Additionally, as an apparatus obtained by simplifying such a coal gasification apparatus, there is, for example, one described in the following PTL 2. The gasification furnace apparatus described in this PTL 2 is obtained by providing a pressure vessel that houses a gasification furnace which gasifies fuel and a gas heat exchanger which performs the temperature control of the produced gas generated in the gasification furnace and steam generation using the sensible heat of the produced gas, and by connecting a pressure equalizer of which one end opens into the gasification furnace and the other end opens into the pressure vessel.